1. Field of the Invention
The present invention relates to a canister vacuum cleaner and, more particularly, to such a vacuum cleaner equipped with automatic operation control for automatically selecting an optimal operation mode.
2. Description of the Background Art
One of a problem associated with a vacuum cleaner has been a control of a rotor brush to avoid clogging, jamming, racing, and other undesirable modes of operation. Although the operation of the rotor brush is greatly affected by a condition of surface to be cleaned (referred hereafter as a floor condition), various propositions to cope with this problem made so far rely for accounting the floor condition either on a manual operation based on a human judgement which can be quite cumbersome or a motion of the rotor brush itself which is actually unreliable when the rotor brush is already in an undesirable mode of operation and which does not reflect the floor condition fully.
Another problem associatd with the vacuum cleaner is that certain floor conditions present a problem in that suction by a power nozzle is to strong to permit a smooth movement of the power nozzle. To cope with this problem, there are some vacuum cleaner which can adjust air flow of a suction fan in accordance with different floor conditions.
However, it has commonly been a manual operation which actually changes the air flow, so that the operation becomes quite cumbersome. For this reason, there have been propositions for automatic control of the air flow of the suction fan, but so far it has been necessary to coordinate the detection of the floor condition performed at the power nozzle and the control of the suction fan performed in the canister, which has commonly been achieved by means of additional signal transmision between the power nozzle and the canister along a suction hose. Such an automatic control mechanism, on the other hand, is associated with increased cost, complicated configuration, and less maneuverability, all of which are highly undesirable for such a common home appliance as a vacuum cleaner.